Technical Field
The present disclosure relates to a method and an apparatus for arc welding.
Related Art
A patent document JP-A-2002-001534 discloses a welding method and a welding apparatus, in which upper portions of base metals which are horizontally butted against one another are joined using TIG (tungsten inert gas) welding.
In the welding method and apparatus based on the conventional art as set forth above, separated fusion may occur. The separated fusion refers to a defect in which base metals do not fuse with each other.
There are two main cases in the separated fusion. The first case is that both of the base metals are fused but the fused portions are separated from each other. The second case is that only one of the base metals is fused.
A cause of the first case could be that there is a large vertical step between the base metals or there is a large horizontal gap between the base metals. A cause of the second case could be that the base metals are not in good contact with the ground electrodes.